Abstract
A composite photocatalyst, a manufacturing method thereof, the kits including the composite photocatalyst, and a bactericide photocatalyst. A composite photocatalyst includes photocatalyst nanocrystals and platinum nanocrystals. The photocatalyst nanocrystals include a compound represented by the following chemical formula (1): A.sup.2+(B.sup.3+).sub.2X.sub.4 chemical formula (1), wherein A.sup.2+ represents Zn.sup.2+, Cu.sup.2+, Fe.sup.2+, Mn.sup.2+, Ni.sup.2+, Co.sup.2+ or Ag.sub.2.sup.2+; B.sup.3+ represents Fe.sup.3+, Mn.sup.3+ or Cr.sup.3+; and X represents O.sup.2-.